Mechanisms regulating tau alternative pre-mRNA splicing Accumulating evidence indicates that pre-mRNA splicing defects and aberrant splicing lead to a range of neurodegenerative disorders. Alternative splicing is critical for tau gene function, and splicing mutations in the human tau gene lead to fronto-temporal lobe dementia (FTLD-tau). Although tau splicing mutations were initially reported in 1998, the mechanisms by which mutations affect tau alternative splicing are still poorly understood, and risk factors as well as genetic modifiers in FTLD-tau remain to be identified. This proposal aims to investigate the mechanisms regulating tau gene alternative splicing. We plan to use molecular, biochemical and cell biological methods to investigate tau alternative splicing and to compare the differential spliceosomal recognition of wild type versus mutant tau transcripts. We have established both in vitro biochemical assays and cell culture systems to investigate tau exon 10 alternative splicing. Using biochemical assays and an expression cloning strategy, we have identified several proteins involved in tau exon 10 alternative splicing in our preliminary studies. A primary neuronal culture system has also been set up to investigate the role of identified factors in neuronal cell death. Molecular dissection of cis- and trans-acting elements important for tau alternative splicing will not only help in understanding the basic mechanisms controlling tau alternative splicing but also reveal new players in pathogenesis of neurodegeneration. We plan to use combined bioinformatics, biochemical, molecular and genetic approaches to study the pathogenetic mechanisms underlying FTLD-tau, one most common neurodegenerative disorders.